Lubricants suitable for hydroforming and other metal manipulating applications

ABSTRACT

The present invention discloses a hydroforming process for metal parts that uses liquid-film and solid-film lubricants. The lubricants used in the invention are particularly useful for die-side lubrication. The process includes a step in which a ductile metal part is over-coated with either the liquid-film or solid-film lubricant. The liquid lubricants preferably include an oil and a optionally a surfactant. The solid lubricants preferably include a hard wax and optionally a surfactant.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.09/957,911 filed Sep. 21, 2001 which, in turn, claims the benefit ofU.S. Provisional Application Ser. No. 60/234,833, filed Sep. 22, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to lubricants used in metal forming processesand, in particular, to lubricants used in hydroforming processes.

2. Background Art

Processes in which metal parts are manipulated or formed typicallyrequire lubricants to reduce equipment wear. These processes includesuch operations as bending, swaging, roll-tapping, drawing, andhydroforming. Hydroforming is a particularly important process in whicha relatively complex metal part is fabricated.

There are two types of hydroforming processes. One is used to form partsfrom sheet metal and the other is used to form parts from metal tubes.Many tube hydroforming applications are currently utilized by theautomotive industry.

In a tube hydroforming process, a workpiece tube is placed in a toolcavity. The geometry of the die cavity corresponds to the externalgeometry of the produced part. The tool cavity is closed by the rammovement of a press. At the same time, the tube ends are loaded by twopunches moving along the tube axis, and an aqueous fluid is pumped intothe tube. As the internal pressure of this pressure-side aqueous fluidis increased, the tube expands until the expanding tube wall contactsthe inner surface of the die, and the part is formed.

There are three types of lubricants involved in the tube hydroformingprocess: a bending lubricant, the pressure-side aqueous fluid mentionedabove, and a die-side lubricant that is used between the workpiece tubeand the die. The bending lubricant is used on the inside of the tube tobend the tube into a desired shape just prior to mounting the tube inthe hydroforming tool cavity. The pressure-side fluid is the aqueoushydraulic fluid used to transmit the pressure to the inside of the tube.Although little lubricity is required of the pressure-side fluid, otherproperties, such as corrosion protection, high pressure stability, andthe ability to reject the bending and die-side lubricants, are importantto the performance. The die-side lubricant is the primary forming fluidin high-pressure hydroforming. It provides the lubricity between theworkpiece and the die.

The demands on the die-side lubricant vary widely. Some light dutyapplications require little of the die-side lubricant. In the case oflower pressure applications, the pressure-side fluid may also be usedsimultaneously to transmit pressure inside the tube and to providedie-side lubrication. As the complexity of the application increases,the importance of the die-side lubricant increases. Furthermore, thedie-side lubricants' compatibility with the pressure-side lubricant andthe removal of the die-side lubricant from the newly formed part areimportant considerations.

SUMMARY OF THE INVENTION

The present invention discloses a liquid film die-side hydroforminglubricant that comprises an oil and a surfactant. The liquid filmdie-side lubricant is typically already a liquid when applied to theworkpiece tube. Preferably, the liquid film die-side lubricant haslubrication properties that are not substantially damaged by contactwith the pressure-side fluid which usually contains water. Furthermore,the liquid film die-side lubricant preferably has high viscosity.

In accordance with another aspect of the present invention, a solid filmdie-side hydroforming lubricant is disclosed. The solid film die-sidelubricant comprises a wax such that the stress value within the die-sidelubricant is at least 540 kPa at 0.75 sec after a compressive stress isimposed. Preferably, the solid film die-side lubricant is a liquid whenapplied to the workpiece tube. The applied liquid then either dries orcures into a solid lubricating film. The solid film die-side lubricanthas lubrication properties that are not substantially damaged by contactwith the pressure-side fluid, which usually contains water. Furthermore,the liquid film die-side lubricant preferably has high viscosity. Whenthe die-side lubricant of the present embodiment is a solid at the timeof emplacement, the die-side lubricant preferably has high hardness andoptionally a high elasticity. The solid film lubricant also optionallyincludes a wetting agent to improve the ability of the composition towet metallic surfaces.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to presently preferred compositionsor embodiments and methods of the invention, which constitute the bestmodes of practicing the invention presently known to the inventor.

For purposes of the present invention, the resistance of a lubricant todamage to its lubrication properties by pressure-side fluid is mostconveniently measured by measuring the coefficient of friction of twometal surfaces, lubricated with the die-side lubricant to be measured,in a sliding friction test at a pressure from 65 to 400 bars and in atwist compression test at a pressure from 675 to 2500 bars. A die-sidelubricant to be tested is first placed on one surface of a substrate ofthe same type of metal as is to be hydroformed in the same manner as ifthe substrate were to be hydroformed, but the substrate in this instancehas a shape suitable for the intended method of measurement ofcoefficient of friction. After the coefficient of friction has beenmeasured, the die-side lubricant layer is sprinkled or otherwise gentlywet with the intended pressure-side fluid for hydroforming or asurrogate for this pressure-side fluid, plain deionized or tap wateroften being an effective surrogate. A volume of the pressure-side fluidor surrogate therefor that is not more than about twice the volume ofthe wetted die-side lubricant film itself should be used, and nosubstantial mechanical force such as would result from high pressurespraying should be used. After a minute or two of contact between thelubricant layer and the pressure-side fluid or surrogate therefor, anyremaining aqueous liquid is allowed to drain away under the influence ofnatural gravity, and the coefficient of friction of the substratebearing the thus-drained die-side lubricant film is again measured. Thedie-side lubricant has sufficient pressure-side fluid-resistance for thepurposes of this invention when the coefficient of friction measuredwith the thus wetted and drained die-side lubricant film does not exceedthe coefficient of friction measured under the same conditions with theoriginally emplaced and unwetted die-side lubricant film by an amountthat is preferably more than about 50 percent of the value of thecoefficient of friction for the originally emplaced and unwetteddie-side lubricant film, more preferably more than about 30 percent ofthe value of the coefficient of friction for the originally emplaced andunwetted die-side lubricant film, and most preferably more than about1.0 percent of the value of the coefficient of friction for theoriginally emplaced and unwetted die-side lubricant film. Inparticularly favorable instances, the coefficient of friction is reducedby contact with the pressure-side fluid or surrogate therefor. All ofthe measurements involved in this determination of the pressure-sidefluid resistance of a lubricant should be made at the intendedtemperature of the hydroforming process itself, or, if the latter isunknown, at a normal ambient human comfort temperature (between 18 and23° C.).

In one embodiment of the present invention, a liquid film die-sidehydroforming lubricant is disclosed. The liquid film die-side lubricantis typically already a liquid when applied to the workpiece tube. Theliquid film die-side lubricant has lubrication properties that are notsubstantially damaged by contact with the pressure-side fluid as definedabove. Furthermore, the liquid film die-side hydroforming lubricantincludes an oil that has a kinematic viscosity measured at 40° C., thatis at least, with increasing preference in the order given, 2.5, 5.0,7.5, 10.0, 12.5, 15.0. 17.5, or 20 stokes. Suitable commerciallyavailable oils include vegetable oils, blown (alternatively called“oxidized”) vegetable oils, polymers of vegetable oils, animal oils, andblown animal oils along with typical petroleum oils. Specific examplesinclude blown canola oil, blown fish oil, canola oil, blown rapeseedoil, and naphthenic oil.

The liquid film die-side hydroforming lubricant (“liquid filmcomposition”) of the present invention optionally further include asurfactant. The surfactant improves the cleaning properties of thelubricant, i.e., the ease of removing residual lubricant. Although anysurfactant may be utilized, preferably non-ionic surfactants are used.The surfactant also preferably improves the lubricity of the liquid filmwhen wetted. Though not restricting the improvement of lubricity to anyparticular mechanism, the surfactant appears to form an emulsified layerwhen wetted that enhances lubricity. However, the amount of surfactantis not so much that the liquid film is deteriorated duringemulsification. The surfactant is preferably present in an amount of0.1% to 10% of the total weight of the liquid film composition, morepreferably in an amount of 1.0% to 5% of the total weight of the liquidfilm composition, and most preferably in an amount of about 2.5% of thetotal weight of the liquid film composition. Preferred surfactantsinclude vegetable oil ethoxylates, ethoxylates of alkyl alcohols,ethoxylates of acetylenic diols, block copolymers of ethylene andpropylene oxides, ethoxylates of alkyl carboxylates such as typicalfatty acids, alkyl polyglycosides, and mixtures thereof. Examplesinclude but are not limited to Chemal DA-6, Chemal DA-9, Chemal LA-4,Chemax CO-5, Chemax CO-16, Chemax CO-25, Chemax CO-30, Chemax CO-36,Chemax CO-40, Chemax CO-80, and Chemax CO-200/50 commercially availablefrom Chemax, Inc. located in Greenville, S.C. Suitable surfactants alsoinclude but are not limited to Surfynol 440 commercially available fromAir Products, TOMAH E-14-5 (poly (5) oxyethylene isodecyloxypropylamine)and TOMAH E-14-2 commercially available from Tomah Products Inc. locatedin Milton, Wis.; NINOL 11CM (a modified coconut diethanolamidesurfactant sold by Stepan, Inc.) TRITON X-100 (octylphenol ethyleneoxide condensate; Octoxynol-9) commercially available from UnionCarbide; and APG 325 CS (decyl polyglucoside) commercially availablefrom Cognis Corporation located in Cincinnati, Ohio. Other suitablenon-ionic surfactants include block surfactants containingpolyoxypropylene hydrophobe(s) and polyoxyethylene hydrophile(s). Inorder to properly function, the surfactant must be soluble ordispersible in the lubricant. The blocks may be homopolymeric orcopolymeric, for example copolymers derived from oxyalkylating withmixtures of ethylene oxide and propylene oxide. Such surfactants areavailable from numerous sources, including the Pluronic®, Tetronic®, andPluronic® R polyether surfactants from BASF Corporation.

In another embodiment of the present invention, a solid film die-sidehydroforming lubricant (“solid film composition”) is disclosed.Typically, the solid film lubricant will be applied to a surface as aliquid which is subsequently dried and cured. The resultant solidlubricant of the present invention preferably has a hardness as measuredat 23-26° C. by the American Society for Testing and Materials (“ASTM”)Procedure Number D-5 that is not more than, with increasing preferencein the order given, 50, 40, 30, 20, 15, 13, 11, 9, 7, 5, or 3. The solidfilm lubricant of the present invention includes solid lubricants thatare characterized by one or more of the following properties whensubjected to a compressive stress within the range from 1.50 to 2.00percent over a time interval of 0.20 to 0.30 seconds at 23-26° C.:

-   -   the stress value within the solid die-side lubricant 0.75 sec        after the compressive stress began to be imposed is at least,        with increasing preference in the order given, 500, 510, 520,        530, 540, 550, 560, 570, or 580 kiloPascals (this unit of stress        being hereinafter usually abbreviated as “kPa”);    -   the stress value within the solid die-side lubricant 100 sec.        after the compressive stress began to be imposed is at least,        with increasing preference in the order given, 300, 350, 400,        450, 500, 510, 520, 530, 540, or 550 kPa; and    -   the residual stress within the solid die-side lubricant 100 sec        after the compressive stress began to be imposed is at least,        with increasing preference in the order given, 75, 80, 82, 84,        86, 88, or 90 percent of the maximum stress induced within the        solid lubricant at any time up to 100 sec after the stress began        to be imposed.        A method of measuring these stress values is described by T H.        Sheilhammer, T. R. Rumsey, and J. M. Krochia in “Viscoelastic        Properties of Edible Lipids,” JOURNAL OF FOOD ENGINEERING 33        (1997), pages 305-320. This paper is hereby incorporated herein        by reference to the extent that it is not inconsistent with any        explicit statement herein. Preferred solid film lubricants        include carnauba wax; candelilia wax; montan wax;        microcrystalline waxes; solid alcohols, particularly primary        alcohols having at least 18 carbon atoms per molecule; solid        esters, particularly esters of primary alcohols having at least        18 carbon atoms per molecule with organic acids, especially        unbranched monoacids, having at least 18 carbon atoms per        molecule; and oxidized petroleum waxes.

The solid film die-side hydroforming lubricant of the present inventionoptionally further includes a surfactant. Although any surfactant may beutilized, preferably non-ionic surfactants are used. The surfactant alsopreferably improves the lubricity of the solid film when wetted. Thesurfactant is preferably present in an amount of 0.05% to 10% of thetotal weight of the solid film composition, more preferably in an amountof 0.1% to 5% of the total weight of the solid film composition, andmost preferably in an amount of about 1% of the total weight of thesolid film composition. Preferred surfactants include vegetable oilethoxylates, ethoxylates of alkyl alcohols, ethoxylates of acetylenicdiols, block copolymers of ethylene and propylene oxides, ethoxylates ofalkyl carboxylates such as typical fatty acids, alkyl polyglycosides,and mixtures thereof. Suitable surfactants also include but are notlimited to Surfynol 440 commercially available from Air Products, TOMAHE-14-5 (poly (5) oxyethylene isodecyloxypropylamine) and TOMAH E-14-2commercially available from Tomah Products Inc. located in Milton, Wis.;NINOL 11CM (a modified coconut diethanolamide surfactant sold by Stepan,Inc.) TRITON X-100 (octylphenol ethylene oxide condensate; Octoxynol-9)commercially available from Union Carbide; and APG 325 CS (decylpolyglucoside) commercially available from Cognis Corporation located inCincinnati, Ohio. Other suitable non-ionic surfactants include blocksurfactants containing polyoxypropylene hydrophobe(s) andpolyoxyethylene hydrophile(s). The blocks may be homopolymeric orcopolymeric, for example copolymers derived from oxyalkylating withmixtures of ethylene oxide and propylene oxide. Such surfactants areavailable from numerous sources, including the Pluronic®, Tetronic®, andPluronic® R polyether surfactants from BASF Corporation.

The solid film die-side lubricant optionally comprises a wetting agent.Utilization of such agents improves the ability of the dry filmcomposition (which is a liquid when applied) to wet metals such as thevarious steel alloys (stainless steel, hot rolled steel, and cold rolledsteel), aluminum alloys, titanium, and copper. It will be recognized bythose skilled in the art, that many wetting agents are surfactants andmany surfactants are wetting agents. Accordingly, a subset of thesurfactants listed above will also function as wetting agents. Suitablewetting agents include, but are not limited to, nonionicfluorosurfactants, anionic fluorosurfactants, ethoxylatedtetramethyldecynediols, acetylenic glycol-based surfactants,dialkylsulfosuccinates, and mixtures thereof. Suitable ethoxylatedtetramethyldecynediols include members of the Surfynol 400 series suchas Surfynol 440 and 420 commercially available from Air Products. Anexemplary acetylenic glycol-based surfactant is Dynol 604 commerciallyavailable from Air Products. Suitable dialkylsulfosuccinates includedioctylsulfosuccinates. The preferred wetting agent is afluorosurfactant which includes both nonionic fluorosurfactants and ananionic fluorosurfactants. Most preferably the wetting agent is anonionic fluorosurfactant. Suitable nonionic fluorosurfactants includefluoroaliphatic ethoxylates and related derivatives. Specifically,Clariant Fluowet OTN and DuPont Zonyl FSN 100 are nonionic surfactantsthat performed well. Fluowet OTN is a proprietary fluoroaliphaticethoxylate commercially available from Clariant. Zonyl FSN 100 is aTelomer B monoether with polyethylene glycol which is a 1:1 mixture ofpoly(oxy-1,2-ethandiyl), α-hydro-Ω-hydroxy-ether withα-fluoro-Ω-(2-hydroxyethyl)poly(difluoromethylene). Suitable anionicfluorosurfactants include fluoroalkylsulfonates and carboxylates with arange of counter ions that include potassium, sodium, and amines.Preferably, the fluorosurfactant is present in an amount of about 0.1%to 1.0% by weight of the dry film composition. More preferably, thefluorosurfactant is present in an amount of about 0.1% to 0.5% by weightof the dry film composition.

The solid film die-side lubricant also optionally includes a corrosioninhibitor and/or a defoamer. Suitable defoamers include neo-decanoicacid. Suitable corrosion inhibitors include soaps or salts of carboxylicacids or organo-sulfonates. Agents capable of adjusting the pH of thelubricant may also be included, such as, for example, amines (e.g.,alkanolamines).

Regardless of whether the die-side lubricant is solid or liquid at thetime of emplacement or whether the die-side lubricant has anaqueous-based liquid after being emplaced, the coefficient of slidingfriction between two metal surfaces with a layer between them of adie-side lubricant to be used in a process according to the inventionpreferably is not more than about 0.3 to 0.5, more preferably is notmore than about 0.1 to 0.3, and most preferably is not more than about0.04 to 0.1.

Furthermore, the die-side lubricant is preferably capable of beingreadily cleaned from the hydroformed object after hydroforming iscomplete, preferably with an aqueous-based cleaner. Preferably, thedie-side lubricant is capable of being cleaned at a temperature nothigher than 55° C., more preferably a temperature not higher than 40°C., and most preferably at a temperature not higher than 28° C. Thispreference is not inconsistent with the need for pressure-side fluidresistance of the die-side lubricant as described above. Typical aqueousbased cleaners are either more acidic or more alkaline than most aqueouspressure-side fluids used in hydroforming. Furthermore, even if thecleaners are neutral, they usually contain other cleaning-promotingingredients such as detersive surfactants that are not present intypical pressure-side fluids for hydroforming.

The die-side lubricant is also preferably easy to separate from thepressure-side fluid should the lubricant become contaminated by thepressure-side fluid. Accordingly, self-segregation of the die-sidelubricant into a separate phase that can be skimmed or drained off froma reservoir of pressure-side fluid is highly desirable.

Finally, the lubricant is preferably easy to apply to the surface to belubricated, without producing any hazard such as flammable, toxic, ornoxious fumes, without requiring any equipment more complicated thansimple spray, immersion, and/or roll coating, and without requiring anyspecial drying equipment. For example, if a die-side lubricant that is asolid when emplaced ready for use can be applied from a latex andallowed to dry in the ambient air without producing any fire hazard orunpleasant odor, there is a substantial practical advantage andtherefore a preference for it over a solid die-side lubricant that mustbe melted to be applied and then quickly cooled to avoid having themelted die-side lubricant run off the substrate being hydroformed.

In another embodiment of the present invention, a process forhydroforming a tube of a ductile solid material is provided. The processcomprises the following steps:

-   -   (I) providing a pressure-side fluid and an openable die having        an interior surface of a shape to which it is desired to have        the hydroformed part of the outer surface of the tube of ductile        solid material conform after the tube has been hydroformed;    -   (II) forming over the outer surface of the tube of ductile solid        material a coating of a die-side lubricant suitable for use in a        process according to the invention as described above, so as to        form a coated ductile tube;    -   (III) emplacing the coated ductile tube within at least a part        of said openable die and closing the die, so that a portion of        the outer surface of the ductile tube that is desired to be        hydroformed is within the closed openable die;    -   (IV) filling the interior of the tube of ductile solid with a        volume of said pressure-side fluid, so that said pressure-side        fluid exerts equal pressure on all parts of the internal surface        of the tube of ductile solid with which the pressure-side fluid        is in physical contact; and    -   (V) applying to said volume of pressure-side fluid filling said        interior of the ductile tube, while the ductile tube remains        emplaced within the closed openable die as recited in        operation (III) above, a sufficient pressure to cause at least a        portion of the outer surface of the coated ductile tube to        conform to the inner surface of the closed openable die.

Only a relatively thin layer of the die-side lubricant is needed forsatisfactory lubrication. More particularly, the average thickness ofthe die-side lubricant layer formed before hydroforming beginspreferably is in the range 0.2 to 200 microns, more preferable in therange 1.0 to 100 microns, and most preferably about 15 microns.Uniformity of the die-side lubricant is not critical. The films may evenbe discontinuous ball-like lumps and aggregates evenly distributed overthe surface of the part.

Preferred lubricants for use according to the invention can be readilyremoved from surfaces of metal ductile tubes, after hydroforming iscompleted, by conventional alkaline cleaners.

Except for use of the characteristic lubricant for this invention asdescribed above, the process conditions for a hydroforming processaccording to the invention are normally the same as those already in usein the art. A process according to the invention is particularlyadvantageous in “high pressure” hydroforming, in which the hydraulicpressure in step (V) of the process as described above is at least 340bars and independently is particularly advantageous in hydroforming coldrolled steel, but is suitable for hydroforming any other ductile solidas well. Hydroforming with these lubes is successful with hot-rolledsteel, cold-rolled steel, and aluminum, both 5000 and 6000 seriesalloys.

The invention may be further appreciated by consideration of thefollowing examples and comparison examples. In all of the tests below,the metal substrate was type ADKQ 95 hot-rolled steel, which is one ofthe most commonly hydroformed substrates.

Test Methods

Cornerfill Test

The cornerfill test is designed to test the properties required by adie-side hyroforming lubricant in the expansion zone of a hydroformingprocess. In these tests, the exterior surface of a welded cylindricalsteel tube was coated with test die-side lubricant and then mounted in adie with a square cross-section that was within one millimeter oftouching the exterior cross-section of the cylindrical steel tube at thecenter of all four walls of the square die, with no weld line at or nearone of these centers of the die walls. The lubricant-coated exterior ofthe steel tube was then sprayed lightly with water before the die wasclosed. The interior of the steel tube was then filled with a volume ofa water-based pressure side fluid, and the pressure in the tube was thenincreased until the tube burst. Sensors detected the pressure at variousstages of expansion, the maximum pressure before the tube burst, and themaximum expansion of the tube. The burst tube was then removed from thedie, and the tube burst location was noted. Then the dimensions of theburst tube were measured and the true thickness strain was calculatedfor seven locations: the four corners and the centers of the three wallsof the square cross-section into which the tube had expanded that didnot include the original welded area. Three of the properties measuredin this type of test are generally considered relevant to performance inactual hydroforming. A higher burst pressure is better than a lower one;a low standard deviation of the true thickness strain is better than ahigher one; and a burst near the center of the tube is better than aburst in any other part of the tube.

Twist Compression Test

A twist compression test is designated to test the properties requiredby a die-side hydroforming lubricant in transition zones near the edgesof expansion zones in hydroforming. In these tests, an annular tool wasrotated under pressure over a flat plate of steel on which the testlubricant had been emplaced. The pressure applied on the lubricatedplate in one set of tests was 10,000 psi and in another was 15,000 psi.These pressures are typical of commercial hydroforming of hot rolledsteel tubes. A plot of the coefficient of friction as a function of timewas generated. The results are reported at 1, 2, and 3 revolutions. Thetest was first conducted dry for each lubricant and then twice after thelubricant had been sprayed lightly with water. Only the average of thelatter two of these measurements is reported below. The tests were alsoperformed on lubricants sprayed with Novacool 9034, a pressure-sidefluid commercially available from Henkel Corporation, Madison Heights,Mich. The lower the coefficient of friction in these tests, the betterperformance the lubricant usually gives in the transition zone.

Sliding Friction Test

The sliding friction test measures the properties of the die-sidelubricant that are important in the “end-feeding zone” of a hydroformingprocess. In this end-feeding zone, the tube being hydroformed does notsubstantially expand or contract its eternal cross-section, although itswalls may thin or thicken. Instead, part of the tube moves laterallyalong the die to allow for expansion in another part of the die. Thisend-feeding is very important in the production of some part designs byhydroforming. The procedure used for this type of test for which valuesare reported here is described in American Society for Testing andMaterials (“ASTM”) Procedure 4173-82, using a compressive pressurebetween the sliding workpieces of 69 bars (1000 psi). (This isofficially an “obsolete” ASTM test method, but it is still useful formeasuring the coefficient of friction in sliding friction.) The lowerthe coefficient of friction in sliding friction, the better is thelubricant in the end-feeding zone.

Solid Film Lubricants

Examples 1-4 provides examples of the solid film lubricants of thepresent invention.

EXAMPLE 1

Component Weight % carnuba wax aqueous 89.5%  emulsion, 22% solids,(Michelman Michem Lube 160) water 8.0% monoethanolamine 0.5% sodiumbenzoate 2.0% Total  100% 

The monoethanolamine reduces the staining by the wax by the slightlyacidic carnuba wax by raising the pH. Finally, the sodium benzoate is acorrosion inhibitor. The carnuba wax is characterized with a hardness ofabout 1 (ASTM-D-5), a particle size of about 0.15 microns, and a meltingpoint of about 85° C.

EXAMPLE 2

Component Weight % microcrystalline wax 99.0 emulsion, 42% solids,(Michelman Michem Lube 124) nonionic surfactant, (Air 1.0 ProductsSurfynol 440) Total 100%

The microcrystalline wax is a mixture of two waxes of hardness 5 and 13using ASTM D-5 and with melting points centered around 68 and 101degrees C. Furthermore, the microcrystalline wax has a particle size ofabout 0.18 microns.

EXAMPLE 3

Component Weight % Fischer-Tropsch wax 99.9 emulsion, 40% solids,(Michelman Emulsion 64540) nonionic surfactant, (Air 0.1 ProductsSurfynol 420) Total 100%

The Fischer-Tropsch wax is characterized with a hardness of about 1(ASTM-D-5), a particle size of about 0.6 microns, and a melting point ofabout 98° C.

EXAMPLE 4

Component Weight % Fischer-Tropsch wax 92.5 emulsion, 40% solids,(Michelman Emulsion 98040M1) nonionic surfactant, (Air 1.0 ProductsSurfynol 440) neodecanoic acid 4.0 KOH, 45% 2.5 Total 100.00

The neodecanoic acid functions as both a corrosion inhibitor anddefoamer. The Fischer-Tropsch wax is characterized as set forth abovefor example 3.

The results of the twist compression measurements for the lubricants inexamples 1-3 are summarized in Tables 1 and 2. TABLE 1 Twist CompressionResults using 6061 T4 Aluminum at 10,000 psi Prewet initial COF @ COF @COF @ Lube Fluid COF 1 rev 2 rev 3 rev example 1 water 0.07 0.06 0.070.09 example 1 9034 0.01 0.03 0.03 0.04 example 2 water 0.01 0.03 0.060.08 example 2 9034 0.01 0.03 0.07 0.10

TABLE 2 Twist Compression Results using Hot-Rolled Steel at 15,000 psiPrewet initial COF @ COF @ COF @ Lube Fluid COF 1 rev 2 rev 3 revexample 1 water 0.01 0.02 0.04 0.06 example 1 9034 0.04 0.04 0.05 0.05example 2 water 0.01 0.03 0.03 0.04 example 2 9034 0.01 0.03 0.03 0.03example 3 water 0.01 0.02 0.03 0.04 example 3 9034 0.01 0.02 0.03 0.04

The coefficient of friction (COF) was determined by the sliding frictiontest for various wetted and unwetted waxes. The results are summarizedin Table 3. Surprisingly, the COF is reduced when the waxes are wetted.TABLE 3 Coefficient of friction for various waxes. Wax COF (Neat) COF(wetted) carnuba wax 0.30-0.20 0.20-0.10 montan wax 0.20-0.18 0.18-0.12microcrystalline wax 0.12-0.10 <0.10 Fischer-Tropsch wax — <0.10Liquid Film Lubricants

Examples 5-8 provide examples of the liquid film compositions of thepresent invention.

EXAMPLE 5

Component Weight % blown canola oil, Z2 97.5 viscosity ethoxylatedcastor oil, 2.5 Chemax CO-5 Total 100.00

In view of the tackiness of blown canola oil, the ethoxylated castor oilis water miscible and makes it easier to wash the composition in example5. The ethoxylated castor oil in provided in such an amount that thewashability of the formulation improved but lubricity of the formulationis only minimally degraded. Small amounts of the ethoxylated castor oilactually improve lubricity. Example 5 has a burst pressure of about10,510 psi; a twist compression coefficient of friction at 10,000 psi ofabout 0.06; a twist compression coefficient of friction at 15,000 psi ofabout 0.05; and a sliding coefficient of about 0.065.

Tables 4 and 5 summarize the twist compression results for thecomposition described by example 5. TABLE 4 Twist Compression Resultsusing 6061 T4 Aluminum at 10,000 psi Prewet initial COF @ COF @ COF @Lube Fluid COF 1 rev 2 rev 3 rev example 5 water 0.06 0.27 0.29 0.28example 5 9034 0.10 0.24 0.32 0.35

TABLE 5 Twist Compression Results using Hot-Rolled Steel at 15,000 psiPrewet initial COF @ COF @ COF @ Lube Fluid COF 1 rev 2 rev 3 revexample 5 water 0.08 0.07 0.09 0.14 example 5 9034 0.09 0.07 0.08 0.07

EXAMPLE 6

Component Weight % canola oil 97.5 ethoxylated castor oil, 2.5 ChemaxCO-5 Total 100.00

EXAMPLE 7

Component Weight % blown herring oil, Z5 95.0 viscosity ethoxylatedcastor oil, 5.0 Chemax CO-5 Total 100.00

EXAMPLE 8

Component Weight % blown canola oil, Z2 47.5 viscosity naphthenic oil,100 SUS 50.0 viscosity ethoxylated castor oil, 2.5 Chemax CO-5 Total100.00

Example 8 has a burst pressure of about 10,510 psi; a twist compressioncoefficient of friction at 10,000 psi of about 0.06; a twist compressioncoefficient of friction at 15,000 psi of about 0.05; and a slidingcoefficient of about 0.065

The coefficient of friction (COF) was determined for mixtures of blowncanola oil and various surfactant. The COF was measure both for neat(unwetted) and wetted mixtures. Table 6 summarizes the results. Thecoefficient of friction is surprisingly reduced in each case whenwetted. Chemal DA-6 is the surfactant ethoxylated decyl alcohol with 6moles of ethoxylation for each mole of alcohol, Chemal DA-9 is thesurfactant ethoxylated decyl alcohol with 9 moles of ethoxylation foreach mole of alcohol, Chemal LA-4 is the surfactant ethoxylated laurylalcohol with 4 moles of ethoxylation for each mole of alcohol, ChemaxCO-5 is the surfactant ethoxylated castor glyceride with 5 moles ofethoxylation for each mole of castor glyceride; Chemax CO-16 is thesurfactant ethoxylated castor glyceride with 16 moles of ethoxylationfor each mole of castor glyceride; and Chemax CO-80 is the surfactantethoxylated castor glyceride with 80 moles of ethoxylation for each moleof castor glyceride. TABLE 6 COF for neat and wetted mixtures of blowncanola oil and surfactant. Lubricant COF at 2350 psi % reduction in COFblown canola oil + 2.5% 0.040 DA-6 blown canola oil + 2.5% 0.025 37.5DA-6 blown canola oil + 2.5% 0.032 DA-9 blown canola oil + 2.5% 0.02812.5 DA-9 blown canola oil + 2.5% 0.024 LA-4 blown canola oil + 2.5%0.017 29 LA-4 blown canola oil + 2.5% 0.037 CO-5 blown canola oil + 2.5%CO-5 0.021 43 blown canola oil + 2.5% CO- 0.035 16 blown canola oil +2.5% CO- 0.022 37 16 blown canola oil + 2.5% CO- 0.036 80 blown canolaoil + 2.5% CO- 0.024 33 80

The COF was determined for neat (unwetted) and wetted mixtures of blowncanola oil and the surfactant Chemax CO-40. Table 7 summarizes the COFfor varying amounts of Chemax CO-40 in blown canola oil, Z2, viscosity.Chemax is an ethoxylated caster glyceride with 40 moles of ethoxylationfor each mole of caster glyceride. Again, the wetted mixtures have lowerCOF than the neat mixture. TABLE 7 COF for neat and wetted mixtures ofblown canola oil and Chemax CO-40. COF at % reduction COF at % reductionLubricant 2900 psi in COF 2900 psi in COF blown canola 0.015 — — — oil +2.5% CO-40 (neat) blown canola 0.012 20% — — oil + 2.5% CO-40 (wetted)blown canola — — 0.034 — oil + 2.5% CO-40 (neat) blown canola — — 0.02332% oil + 2.5% CO-40 (wetted) blown canola — — 0.042 — oil + 5% CO-40(neat) blown canola — — 0.039  7% oil + 5% CO-40 (wetted)

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A process for hydroforming a tube of ductile solid material, theprocess comprising: (I) providing a pressure-side fluid and an openabledie having an interior surface of a shape to which it is desired to havethe hydroformed part of the outer surface of the tube of ductile solidmaterial conform after the tube has been hydroformed; (II) forming overthe outer surface of the tube of ductile solid material a coating of adie-side lubricant selected from the group consisting of:
 1. a liquidlubricant comprising an oil and a surfactant;
 2. a solid lubricantcomprising a wax wherein the stress value within the solid die-sidelubricant 0.75 sec after the compressive stress began to be imposed isat least 500 kPa; the stress value within the solid die-side lubricant100 sec. after the compressive stress began to be imposed is at least300 kPa; and the residual stress within the solid die-side lubricant 100sec after the compressive stress began to be imposed is at least 75percent of the maximum stress induced within the solid lubricant at anytime up to 100 sec after the stress began to be imposed; and
 3. mixturesthereof. (III) emplacing the coated ductile tube within at least a partof said openable die and closing the die, so that a portion of the outersurface of the ductile tube that is desired to be hydroformed is withinthe closed openable die; (IV) filling the interior of the tube ofductile solid with a volume of said pressure-side fluid, so that saidpressure-side fluid exerts essentially equal pressure on all parts ofthe internal surface of the tube of ductile solid with which thepressure-side fluid is in physical contact; and (V) applying to saidvolume of pressure-side fluid filling said interior of the ductile tube,while the ductile tube remains emplaced within the closed openable dieas recited in operation (III) above, a sufficient pressure to cause atleast a portion of the outer surface of the coated ductile tube toconform to the inner surface of the closed openable die. 2-7. (canceled)8. The process of claim 1, wherein the oil is selected from the groupconsisting of vegetable oils, blown vegetable oils, polymers ofvegetable oils, animal oils, and blown animal oils, and mixturesthereof.
 9. The process of claim 1, wherein the oil is selected from thegroup consisting of blown canola oil, blown fish oil, canola oil, blownrapeseed oil, naphthenic oil, and mixtures thereof.
 10. The process ofclaim 1, wherein the surfactant is a non-ionic surfactant.
 11. Theprocess of claim 10, wherein the surfactant is selected from the groupconsisting of vegetable oil ethoxylates, ethoxylates of alkyl alcohols,ethoxylates of acetylenic diols, block copolymers of ethylene andpropylene oxides, ethoxylates of alkyl carboxylates, alkylpolyglycosides, and mixtures thereof.
 12. (canceled)
 13. The process ofclaim 10, wherein the surfactant is present in an amount of about 1.0%to 5% of the total weight of the liquid film composition.
 14. (canceled)15. The process of claim 1, wherein the wax is selected from the groupconsisting of carnauba wax, candelilla wax, montan wax, microcrystallinewaxes, solid alcohols, solid esters, and oxidized petroleum waxes. 16.The process of claim 1, wherein the wax is a primary alcohol having atleast 18 carbon atoms per molecule.
 17. The process of claim 1, whereinthe wax is an ester of a primary alcohol having at least 18 carbon atomsper molecule with an organic acid.
 18. The process of claim 1, whereinthe organic acid is an unbranched monoacid, having at least 18 carbonatoms per molecule.
 19. The process of claim 1, wherein the solidlubricant further comprises a surfactant.
 20. The process of claim 19,wherein the surfactant is a non-ionic surfactant.
 21. The process ofclaim 19, wherein the surfactant is selected from the group consistingof vegetable oil ethoxylates, ethoxylates of alkyl alcohols, ethoxylatesof acetylenic diols, block copolymers of ethylene and propylene oxides,ethoxylates of alkyl carboxylates, alkyl polyglycosides, and mixturesthereof.
 22. The process of claim 19, wherein the surfactant is presentin an amount of about 0.05% to 10% of the total weight of the dry filmcomposition.
 23. The process of claim 19, wherein the surfactant ispresent in an amount of about 1.0% to 5% of the total weight of the dryfilm composition.
 24. (canceled)
 25. The process of claim 1, wherein thesolid lubricant further comprises a wetting agent.
 26. The process ofclaim 25 wherein the wetting agent is selected from the group consistingof nonionic fluorosurfactants, anionic fluorosurfactants, ethoxylatedtetramethyldecynediols, acetylenic glycol-based surfactants,dialkylsulfosuccinates, and mixtures thereof.
 27. (canceled)
 28. Theprocess of claim 25 wherein the wetting agent is present in an amount of0.01% to 1.0% of the weight of the dry film composition.
 29. The processof claim 25 wherein the wetting agent is present in an amount of 0.1% to0.5% of the weight of the dry film composition.
 30. A liquid filmlubricant comprising: an oil; and a surfactant, wherein the liquid filmlubricant has the characteristic that the coefficient of friction isreduced when the liquid film lubricant is wetted as compared to thecoefficient of friction of the liquid film lubricant is unwetted. 31-37.(canceled)
 38. A solid film lubricant comprising: a wax; and asurfactant, wherein the solid film lubricant has the characteristic thatthe coefficient of friction is reduced when the solid film lubricant iswetted as compared to the coefficient of friction of the solid filmlubricant is unwetted. 39-41. (canceled)
 42. The solid film lubricant ofclaim 38, wherein the organic acid is an unbranched monoacid, having atleast 18 carbon atoms per molecule. 43-44. (canceled)
 45. The solid filmlubricant of claim 38, wherein the surfactant is present in an amount ofabout 0.05% to 10% of the total weight of the dry film composition. 46.(canceled)
 47. (canceled)
 48. The solid film lubricant of claim 38further comprising a wetting agent.
 49. The solid film lubricant ofclaim 48 wherein the wetting agent is selected from the group consistingof nonionic fluorosurfactants, anionic fluorosurfactants, ethoxylatedtetramethyldecynediols, dialkylsulfosuccinates, and mixtures thereof.50. (canceled)
 51. The solid film lubricant of claim 48 wherein thewetting agent is present in an amount of 0.01% to 1.0% of the weight ofthe dry film composition.
 52. The solid film lubricant of claim 48wherein the wetting agent is present in an amount of 0.1% to 0.5% of theweight of the dry film composition.
 53. A solid film lubricantcomprising: a wax; and a wetting agent, wherein the solid film lubricanthas the characteristic that the coefficient of friction is reduced whenthe solid film lubricant is wetted as compared to the coefficient offriction of the solid film lubricant is unwetted.
 54. (canceled) 55.(canceled)
 56. The solid film lubricant of claim 53, wherein the wax isan ester of a primary alcohol having at least 18 carbon atoms permolecule with an organic acid.
 57. (canceled)
 58. (canceled) 59.(canceled)
 60. (canceled)
 61. (canceled)